Xinhua News Agency, Beijing, February 12th Title: Reporter's Notes: The innovation of this rocket starts with a "big head"

Xinhua News Agency reporters Song Chen and Chen Kaizi

"big head" and "thick neck" are the first prominent visual impressions of reporters who saw the Long March 8A launch vehicle. Even if you stand up from the open space under the launch tower, the fairing with a diameter of 5.2 meters is still a huge monster.

"There are great questions hidden in the big head!" Fan Chenxiao, designer of the First Academy of China Aerospace Science and Technology Corporation, told reporters that this cute rocket is an innovative design based on the Long March 8 launch vehicle to meet the needs of the future satellite Internet low-orbit satellite network launch.

"The Long March 8A launch vehicle used a 3.35-meter-diameter universal hydroxide final stage with a 5.2-meter-diameter fairing for the first time. The new combination is more coordinated, has a larger carrying capacity, higher carrying efficiency, and better mission adaptability." Song Zhengyu, chief designer of the Long March 8A launch vehicle of the First Dean of China Aerospace Science and Technology Corporation, said.

"The main goal of innovation is to reduce comprehensive costs and achieve high-frequency launches." Song Zhengyu admitted that the driving force for innovation is due to the rapid development of China's aerospace in recent years. Now the demand for medium- and low-orbit satellite launches is growing, allowing the rocket R&D team to continue to explore on the road of pursuing efficiency and economy.

"The Long March 8A launch vehicle has a capacity of 700 kilometers of solar synchronous orbit, which can cover the launch needs of mainstream orbits, especially the medium and low orbit loads in the next 5 to 7 years." Fan Chenxiao said proudly at the rocket on the tower.

After 28 months of careful development and full verification of more than 40 large-scale ground tests, a series of key technical problems of the new rocket have been overcome by the development team one by one.

When talking about the scene that impressed the players the most, it was the full system test run of the general hydroxide and oxygen final stage of the Long March 8A launch vehicle. "That test was the first test run of the hydrogen and oxygen module power system in 10 years in China, and it was also the first test run of the co-bottom module power system in 30 years. As the largest test in the development of the Changbajia rocket, the preparation workload is huge and the cycle is extremely tight. It is almost impossible to complete according to the conventional process." Zhang Junning, designer of the First Academy of China Aerospace Science and Technology Corporation, said.

"Faced with challenges, everyone is holding back their energy, gathering their hearts and minds, and not afraid of hardships." Zhang Junning said that the final assembly needs to be completed before the final test of General Hydrogen and Oxygen test, which usually takes 2 months, but this time, the final assembly work was completed in just 25 days.

In response to the problem of difficulty in controlling caused by the "big head" structure, the development team repeatedly carried out simulation tests to verify to ensure that the closed-loop plan is feasible; in the face of the impact of the test boundary of the tank on the test results, they spent a few days and completed the test boundary plan design, product production and other work in a short time, ensuring that the entire box passed the static test assessment on time; due to the tight overall time, the development team went to three places in one week at the busiest time and carried out three tests in parallel to ensure that the development progress was carried out on time...

"Originally, it took 1 day of installation time, but now it has been reduced to half a day." "It turned out that two people had to carry and walk, but now one person can carry and walk." What saved time and effort by the operators on the launch site was the electrostatic pressure servo product that realized the first flight application in the aerospace field.

Lan Tian, ​​designer of the First Academy of China Aerospace Science and Technology Corporation, introduced that the development team replaced the rocket's second-stage servo supporting products from electro-hydraulic servo to electrostatic pressure servo. Compared with the original, while ensuring reliability, the newly developed electrostatic pressure servo has a weight of 30% to 40%, and the appearance is simpler. Staff only need to install the servo mechanical interface, which is more convenient and faster to operate.

"Not only that, electrostatic pressure servo is an electric drive product. After the arrow is loaded on the ground, the entire arrow can be tested according to the system. The work before the arrow is loaded is cancelled, which can further simplify the launch site testing process." Lan Tian said.

"Faced with the subsequent high-density launch needs, our pace of optimizing and improving the rockets will not stop." Looking at the Long March 8A launch vehicle that flew into the sky and explored the sky, Song Zhengyu told reporters that innovation is the inexhaustible driving force for the development of the Long March series of rockets, and China's aerospace will surely go to the farther sky through continuous innovation.